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# File activerecord/lib/active_record/validations.rb, line 135def default_error_messagesActiveSupport::Deprecation.warn("ActiveRecord::Errors.default_error_messages has been deprecated. Please use I18n.translate('activerecord.errors.messages').")I18n.translate'activerecord.errors.messages'end

Before Rails 2.2 you could globally customize
the default validation error messages by changing
AR::Base.default_error_messages. The messages have now been moved
to i18n, so to customize them in 2.2 and up, just create a
locales/ folder in your config/ folder, copy
activerecord/lib/active_record/locale/en.yml (in Rails source) to config/locales/en.yml,
and then change the strings inside. As szeryf indicated below, the
strings of interest are activerecord.errors.messages.